Differential variable-gain LNA for UWB system

This paper introduces an 1~12 GHz differential 2-stage variable-gain low-noise amplifier (VGLNA) using 0.25 μm SiGe:C BiCMOS commercial process technology for ultra-wideband (UWB) system. The results of the fabricated monolithic microwave integrated circuit (MMIC) amplifier show 18 dB gain with a 3 dB frequency band of 1.3~11.9 GHz and noise figure of less than 5 dB under the bias condition of 2.5 V supply voltage and 55 mW total dc power consumption. The gain-control range (GCR) is from -17 dB to +18 dB. The chip size of the manufactured VGLNA is 0.99 mm² including all testing pads for RF and dc probes.